Eliminates most trailer movement from your trailer's existing stabilizing jacks. Adds support from the jack leg or foot to the trailer's frame. Unique swivel mount adapts to most crank-down trailer jacks and works at various jack angles. Uses 3/4" crank handle (not included) to lock and unlock Lock-Arm. Simple one-time, bolt-on application. Two lock-arms and complete mounting hardware included. Mfr. lifetime warranty. Internet & Catalog Exclusive! | BAL Lock-Arm Stabilizing Bar